5.4. On the Eve of Revolution
At present, telecom providers, banks, and so on build their own local and closed database about clients. A given client is registered individually in each of the systems, and these data are closely guarded (see example in Figure 5.1). Companies do not usually exchange these data with one another12 due to legal restrictions (e.g., data protection), obligations to a client in the scope of confidentiality, the fear of losing clients, or legal claims due to data leakage.
Figure 5.2 shows hypothetical warehouse data about clients, where Ω is identified as a client:
Figure 5.1. Local data warehouses—client data ...